Silent chain.



J. C. HOWE.

SILENT CHAIN.

APPLlcATloN man Nov. 13. '1914. l l LQL'Y.. Patented Oct. 17,y 1916.

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lJOHN' CLARK HOVEE,y 0F INDIANAPOLIS, INDIANA.

SILENT CHAIN.

'0 all whom t may concern Be it known that I, JOHN C. Hown, a citizen of the United States, residing at Indianapolis, in the county of Marion and State of Indiana. have invented a new and useful Silent Chain, of which the following is a specification.

It is the object of my invention to provide a silent chain which shall have rolling bearing surfaces of maximum extent between successive links of the chain and maximum bearing surfaces betweenthe chain and the associated sprocket wheel whereby the maximum amount of power can be transmitted' with a minimum of friction; and todo this with a minimum number` of parts.

In other words it is my object to avoid the necessity for the great number of interdigitated links usually found in silent chains, and at-the same time to decrease the wear on and to increase the bearing surfaces of the chain over those present in the ordinary silent chains.

In carrying out my invention, I make each articulation of two'parallel transverse members or cross bars which roll on eachother, and. which at the same time practically rotate relatively to each other substantially about an axis which is the pivotal axis between adjacent links, and provide these two cross bars with plane gripping surfaces for engaging the sprocket teeth of the associated sprocket wheel and I rigidly connect the two farthest separated crossbars of each two adjacent articulations by one or more longitudinal connectingmembers. Usually I provide two of these longitudinal connecting members for each pair of cross bars thus interconnected, these two cross bars and two connecting members together i forming a link of the chain, and to do ty is I permit one of the cross barsat each articulation to project through holes in the connecting members fixed to the other cross bar at such articulation, this cross bar fitting sufficiently closely in the hole to-prevent back lash but being freely rotatable therein to the extent of the necessary angle of articulation.

The accomlmnying drawing illustrates my invention.

Figure 1 is a view showing a chain embodying my .invention and associated with a sprocket wheel, the chain being partly in elevation and partly in section in severalv di'erent planes; Fig. 2 is an enlarged plan view of a fragment shown inFig. 1; Fig. 3

Specification of Letters Patent.

Patented fom-..- 17, 1916.

Application led November 13,1914. Serial No. 871,882.

is a'side elevation of the chain embodying my invention and articulablein eitherI direction; and Figs. 4 and 5 are elevations of the two kinds of connecting members used in the chain shown in Fig. v1. i

yAt each'articulation of the chain, there are two parallel transverse' members or cross bars-10 and 11. The corresponding or farthest removed cross bars 10 and 11 of each two adjacent articulations are rigidly interconnected by'longitudinal connecting members or side b ars 12 and 13 fixed to such cross bars, each pair of interconnecting cross bars Aand their connecting members forming a link of the chain, and the links 10-12 alternating in thel chain with the links- 11-13. The connecting members or side bars 112 and 13 extend from their associated cross bars 10 and 11 at each articulation past lthe cross bars 11 and 10 respectively of such articulation. The connecting members 12.

are the outer members in the forms illustrated so that holes 14 mustbe provided in the inner connecting members 13 for permitting the cross bars 10' to pass freely through to the outer connecting members 12, the ends of the cross bars conveniently fitting tightly in holes 16 in the connectingmembers 12 and-being riveted in place (as apparent from Flg. 2),and the ends of the cross bars- 11 fitting tight in holes 17 in the connecting members 13. The holes 14 and 17 run into each other,` in reality forming a single hole. The connecting surfaces of the cross bar 10 and the holev 14 are preferably circular cylindrical surfaces having a sliding it one withinthe other-and having as their common axis the: axis 18 about which the two links substantially articulate, the hole 14 being of suliciently greater angular extent than that part of theJ cross bar 10 which fits into itto allowthe necessary sliding of the cross bar in the hole for obtaining the desired articulation. The shape of the engaging walls of the cross barV 10 and the hole 16 or of the cross bar 11 and the hole 17 is not particularly material, save that for'firmness of gripping such engaging walls should not be wholly circular cylindrical and for4 convenience of manufacture they conform quite generally to the adjacent parts of the cross bars 10 and 11. An inward projection 20 helps to clamp the cross bar 11 'in the hole 17, this projection also separating theholes 14 and 1 at one end. The cross bars 10 and 11 are both provided with shoulders 21 which bear against the inner faces of the lconnecting members' 13 to help position the4 parts relatively to each other.

vThe cross bars 10 or 11 of any link have outwardl facing plane surfaces 25' which are at al Xed angle with each other tand are each at half that angle to the line 26 erected perpendicular to and bisecting the line'27 joining the two axes of articulation between such link and the adjacent links. Convention ally, the first-named angle is 60 and the second 30', as such are the ordinary angles used in silent chains. These plane surfaces coperate" with plane surfaces 30 on the teeth 31 of the associated sprocket wheel 32, the: adjacent faces of each tooth and the second tooth from it forming this same' angle of 60" so that a planar engagement between the cross bars 10 and 11 and the teeth of the sprocket wheel is obtained. This planar engagement extends the full length of the cross bars 10 and 11 between the connecting members 13, and these connecting members 13 project down along the sides of the teeth 31 so`as to act as guides for the chain. Each cross bar 10 and 11 may have either one plane surface 25, as shown in Fig. 1, or two such surfaces, as shown in Fig. 3, according as' the chain is to" articulate in one or both directions, as in some cases a bending of the chain in both` directions is necessary but more frequently a bending in one direction is all that is required.

The two cross'bars 10 and 11 of each articu lation have interengaging surfaces 34 and 35 respectively, which roll on each other as articulation takes place. These two surfaces 34 and 35 engage throughout the lengthy of the cross bars 10 and 11. The shape of the surfaces 34 and 35 is such that as they roll on each other the two cross bars 10 and llas nearlyas possible rotate relatively to 'each other about the desired axis of articulation 18. While Strictly speaking this rotation is not accurately a true rotation about the axis 18, it is quite close to it forpractical purposesv for the small angle of articulation which is used in ordinary chains if the sur- I faces 34 and 35 are made as parts of circular cylindrical surfaces which each have a radius substantially equal to that of thel engaging sliding surfaces of the cross bar 10 and the hole 14 and v`which each have an axis 3G on the'line 27 at a distance equal to. such radius in one direction or the other from the substantial axis of articulation 18. If the angle lof articulation is unusually great, the radius used for the surfaces 34 and may be somewhat less than just stated, the axis 36 for each surface still being on the line 27. The rolling surfaces 34 and 35 may extend only .on the one side 'of the line 27, as shown in Fig. 1, or on both sides thereof, as shown in Fig. 3, according as the articulatlon 1s to be 1n one or both directions from a stralght line.

removed from the substantial axis of ar- If these rolling surfaces extend only on one side of the line 27, the cross bars 10 and 11 may be provided with plane surfaces 40 and 4l tangent to the surfaces 34 and 35 at the line 27 to limit the articulation to one direction, the lower ends of these plane surfaces 40 and Y41 being c'ut away, conveniently along curves 42, to allow the more ready escape of any dirt between such surfaces; The angle to which the articulation may extend need not be limited save by the size ofthe sprocket wheel, as illustrated in Fig. 1, but if desired it may be limited'by plane surfaces 43 tangent to the surfaces 34 and 35 at points ticulation 18 by the desired limiting angle of articulation, as illustrated in Fig. 3. This limiting of the angle of articulation is desirable in the doubly bending chain shown in Fig. 3, so as to make the'surfaces 25 of sufficient length, as such surfaces would be cut off if the rolling surfaces 34 and 35 were continued to the extent in which they are shown in Fig. 1.

In practice, assuming that the chain shown in Fig. 1 is traveling in the direction shown by the arrow,'the force is transmitted from one pair of connecting members 12 to the cross bar 10 at their hindmost ends, and from this cross bar 10 is transmitted to the cross bar'11 directly in front of it'and forming with it a joint of articulation, and from this cross bar 11 to the two connecting members 13 extending rearwardly therefrom, and from these connecting members 13 to the cross bar 11 at their hindmost ends, and from this cross bar,11 to the cross bar 10 directly in front of it and forming with it a joint o1' articulation,- and from this cross bar 10 to the two connecting members 12 extending rearwardly therefrom, and so on through the chain. The force is transmitted from the cross bars 10 or 11 to the associated connecting members 12 or 13 respectively by the connections between the latter and the ends of the cross bars, and as transmitted between the two cross bars 10 and 11 at each articulation by the interengaging rolling surfaces 34 and 35, the line of interengagement varying according to the angle of articulation which has been taken. The force is thus trans-V mitted between associated cross bars '10 and 11, and also between such cross bars and the sprocket teeth with which they are in enga gement, along the full length of such members and of the rolling surfaces 34 and 35 or the surfaces 25. Thus the full width of the Y sprocket is used for receiving the force from the chain, and the amount of force which can be transmitted is consequently greater than if the engagement of the chain with thel sprocket wheels was along merely a plurality of portions of such width as is the case with the ordinary silent chain. In addition, because of the rolling of the cross bars l0 and lfixed relatively to them both, each of said I cross bars having a rolling engagement with each other at each joint of articulation, and

connectingdmembers each fixed` to the two,

farthest removed cross bars at two adjacent joints of articulation, the interengaging rolling surfaces of the two cross bars being such that as they roll they also rotate relatively to each other approximately about an axis cross bars having a plane surface for engagement with the tooth of a sprocket wheel.

2. A silent chain comprising two parallel cross bars having a rolling engagement with each other` at each joint of articulation, and connecting"members each fixed to the two farthest removed cross bars at two adjacent joints of articulation, each of said cross bars having a plane surface for engagement with the tooth of a sprocket wheel.

3. A silent chaincomprising two parallel cross bars having a rolling engagement with each other at. each joint of articulation, and connecting members each ixed to the two farthest removed cross bars at two adjacent joints of articulation, each of said cross bars having a plane surface for engagement with the tooth of a sprocket wheel, the two plane surfaces on the two cross bars which are :interconnected by a connecting member being at a fixed angle to each other. f

l. A silent chain comprising a plurality of links each of which comprises a longitudinal member and two cross bars, adjacent links over-lapping so that a cross bar of each of the adjacent links is located between the two cross bars of a link, and cross bars of adjacent links being parallel and engaging on convex cylindrical surfaces on both cross bars on which surfaces they roll relatively to each other as articulation occurs, the cross bars of each linkbeing provided with plane surfaces for eng. ing -the teeth of a sprocket wheel and the wo plane surfaces on each link being at'a ixed angle from each other.

5. A silent chain comprising a plurality of links each of which comprises a longitudinal member and two cross bars, adjacent links over-lapping so that a cross bar of each of the adjacent links is located between the two cross bars of a link, and cross bars of adjacent links being parallel and engaging on convex cylindrical surfaces on both cross bars on which surfaces they roll relatively to each other as articulation occurs, the cross bars of each link being provided with plane surfaces for engaging the teeth of :rsprocket wheel.

6. A silent chain comprising aplurality of links each of which comprises a longitudinal member and two cross bars, adjacent links over-lapping so that a cross bar of each of the adjacent links is located between the two cross bars of a link, and cross bars of adjacent links being parallel and engaging on cylindrical surfaces, the cross bars 'of each link being provided'with plane surfaces for engaging the teeth of a sprocket wheel.

7. A chain comprising a plurality of links eachof which comprises a longitudinal' member and two cross bars, adjacent links over-lapping so that a cross bar of each of the adjacent links is located between the two cross bars of a link, and cross bars of. adjacent links being parallel and rollingly engaging on convex cylindrical surfaces, some of the longitudinal members being provided with guide holes and one of each pair of engaging cross bars having a slidingA fit in one of such guide holes in a longitudinalv member of the adjacent link so as to hold such -two'cross bars in rolling inter-engagement, and the cross" bars having exposed portions which are out of the. plane of the connecting members forcooperating with the teeth of a sprocketwheel.

8. A c hain comprising a pair of cross bars havmg a rolling engagement with each otherv at-each joint of articulation, and a pair of connecting members extending from cross members having a. plane engaging surface for engaging the tooth of a sprocket wheel across the full width of the latter. 9. A chain comprising a pair of cross bars having a rolling engagement with eachother at each joint of articulation, and a pair vof connecting members extending from each cross bar past the other cross bar to the far cross bar at the adjacent joint of articulation, the two cross bars at each joint of articulation being parallel and engaging each other on cylindrical surfaces, and each of said cross members. having a plane engaging surface for engaging the tooth of a sprocket `wheel across the full width of the latter.l j

10. A chain comprising a pairof cross bars having a rolling engagement with each other at each joint of articulation, and a pair of connecting `members extending from each cross bar past the other cross' bar to the far cross bar at the adjacent joint of articulation, the two cross bars at each joint of articulation being parallel and -rollingly engaging each other on convex cylindrical surfaces, some of the connecting members being provided with guide holes and one of the cross bars at each joint of articulation having a sliding fit in such a guide hole in the connecting member-"Which extends past it to the coperating cross bar so that the two cross bars of the -pair are held in rolling engagement with each other,

and the cross bars having exposed intermediate portions which are between and out of the planes of the connecting members for cooperating with the teeth of a sprocket wheel.

11.- A chain comprising two parallel cross bars having a rolling engagement with eacli other at each joint of articulation, connecting members each fixed to the two farthest Varticulation havinga sliding it in such a guide hole in a connecting member which is iixed to the coperating cross bar so that the two cross bars at such joint of larticulation are held in rolling engagement with each other, and they cross bars having ex- A:se

posed portions which are out of the plane of the connecting members for cooperating with the teeth of a sprocket wheel.

12. A chain comprising two parallel cross bars having a rolling engagement with each other at each joint of articulation, the interengaging rolling surfaces ofthe two cross bars both -being cylindrically convex, con-- necting members each fixed to the two farthest removed cross bars at two adjacent joints of articulation, some of the connecting members being provided with guide holes and one of the ycross bars at each joint of ar-l ticulationhaving asliding t in suchaguide j links each of whichcomprises a longitudinal hole in a connecting member which is fixed to the coperating cross bar so that thev two crossbars at such joint of articulation are held in rolling engagement with each other, and the cross bars having exposed portions which are out of the plane of the connecting members .for coperatingwith the teeth of a sprocket wheel.

13. A chain comprising a plurality of links each of which comprises a longitudinal member and two cross bars, adjacent links over-lapping so that a cross bar of each of the adjacent links is located between the two cross barsv of 'a link, cross bars of adjacent links being parallel and engaging on convex cylindrical surfaces on both cross bars on which surfaces they rollrelatively to each other as articulation occurs, some of the longitudinal members being provided with guide holes and one of each pair of cooperating cross bars having a sliding fit in such a guide hole ina longitudinal member of the adjacent link so that the two convex cylindrical surfaces on the cross bars are held in rolling engagement with each other, and the cross bars having exposed portions which are out of the plane of the connecting members for coperating with the teeth of a sprocket wheel.

14. A chain comprising a pair of cross bars having a rolling engagement with each other at each joint of articulation, a' pair of connecting members extending from each cross bar past the other cross bar to the far cross bar at the adjacent'joint of articulation, the two cross bars at each joint of articulation being parallel and engaging each other on convex cylindrical surfaces 'on which they roll relatively to each other as articulation takes place, some of the connectving members being provided with guide holes and one of the cross bars at each joint of articulation having a sliding t in such a uide hole in a connecting member of the adjacent link so that the two convex cylindrical surfaces on the two cross bars at each joint of articulation are held in rolling engagement with each other, and the cross bars having exposed intermediate portions which are between and out of the planes of the connecting members for coperating with the teeth of a sprocket wheel.

15. A chain comprising a plurality of links each of which comprises a longitudinal member and two cross bars, adjacent links overlapping so that a cross bar of each of the adjacent links is located between the .two cross bars of a link, and cross bars at overlapping endsv of adjacent links being parallel and having a rolling engagement on each other so that they roll relatively to each 4other as articulation occurs, each cross bar being provided with a plane surface for engaging a tooth of a sprocket wheel.

16. A chain comprising a plurality of the adjacent links is located between the two Y cross bars of a link, and each cross bar being provided with a plane surface for engaging a tooth of a sprocket wheel.

17. A chain comprising a plurality of links each of which comprises a longitudinal member and two cross bars, adjacent links overlapping so that a cross bar of each of the adjacent links is located between the two cross bars of a link, and each cross bar being provided with a plane surface for engaging 'a tooth of a sprocket wheel and also provided with a bearing surface for transmitting forces from the link of which it forms part to the adjacent link.

iio

18. A chain comprising a plurality of links each of which comprises two side bars and two cross bars, adjacent links overlapping so that a cross bar of each ofthe adjacent links is located between the two cross bars of a link, each cross bar being provided with a plane surface for engaging a 'tooth of a sprocket wheel, and the links be'- cent links is located betweenthe two cross` bars of a link, each cross bar being provided with a plane surface for engaging a tooth of a sprocket wheel and also provided with a bearing surface for transmitting forces from the link of which it forms part to the wide and narrow, the cross bars of the wide links projecting through the side bars'of the narrow links.

In' witness whereof, I have hereunto set my hand at Indianapolis, Indiana, this 11th day 'of November, A. D. onev thousand nine hundred and fourteen.

JOHN CLARK Witnesses:

FRANK A. FAHLE, JOSEPHINE GABPER. l

adjacent link, and the links being alternately 

